1. Field of the Invention
This invention relates to the recovery of refractory metal carbides from contaminated uncemented refractory metal carbide powders. More particularly, it relates to a simple process wherein the refractory metal carbides are recovered as carbides.
2. Prior Art
In the production of cemented refractory metal carbides scrap materials are produced. These scrap materials can result from problems in a manufacturing step and can be either refractory metals in their cemented or uncemented state. For example, the binder is blended with refractory metal carbides generally in a ball mill. Too long milling produces a material which is too fine for some types of cemented carbides. Furthermore, there can be a contamination of the refractory metal carbide with iron and nickel. These materials are scrap materials and if no recovery of the valuable refractory metal is achieved, the process becomes more expensive. Cemented carbides, that is, after the binder is added and the material is then sintered, can also be out of specification and scrap material is produced. Most processes which heretofore have dealt with the reclamation of refractory metal carbides have been directed toward the reclamation from the cemented carbide state. It is believed apparent that the problems are different with materials in the cemented state and in the powdered state. Inherently, the processes used for metal recovery from cemented carbides is more difficult and time-consuming. It is believed to be more efficient if a simple process can be used to purify the refractory metal carbides which are in the uncemented or unsintered state yet are contaminated or are in a form which is not desirable for incorporation in a manufacturing process. It is believed, therefore, that a process which is simple and allows the recovery of refractory metal carbides in the carbide state and does not require the refractory metal values to be chemically processed and upgraded would be an advancement in the art.